Recently I was anaesthetising an adult with a congenital syndrome. I was quite worried about the airway—but in the end it wasn’t that which caught me out. She had no congenital heart disease, but had a pericardial effusion drained a few years previously. I was quite sparing with the induction agents as I wanted to maintain spontaneous respiration, but nonetheless…
About 5 minutes after induction, I noticed the blood pressure was 54/28.
T/F At low levels of blood pressure, the NIBP tends to give spuriously low values.
T/F The most accurate component of the NIBP is the mean.
At the same time, her saturation dropped to 88, even though she was breathing 100% oxygen. The pleth had a good volume and looked normal.
T/F The fall in SpO2 was most likely to be artifactual.
I gave three doses of 1mg metaraminol, but, although the saturation improved, the blood pressure remained in the low 70s. Heart rate was in the 40s. Worried that I might see another fall in saturation I decided to run a noradrenaline infusion.
In such a situation, the most appropriate vasoactive agent would be:
After a 20µg bolus dose of noradrenaline, the heart rate dropped to 28.
T/F The most likely cause of the fall in heart rate is alpha 1 receptor agonism in the SA node.
I found out, after the (otherwise uneventful) operation, that she normally has quite a low blood pressure. A good reminder that, when having trouble with anaesthesia, one should first look to the proximal end of the needle.